Presenter: Teresa Gibson (Thomson Reuters. Health Outcomes)
Discussant: Amy DavidoffUniversity of Maryland
Background: Maintenance of health and well being for patients with a chronic, progressive condition often requires pharmaceutical management and adherence to a regimen of physician visits, screening tests and laboratory tests to manage health and slow disease progression. We investigate adherence to a regimen of diabetes care services and its implications by first examining extent of covariation in adherence to the individual components of regimen of diabetes care including prescription drug filling behavior, laboratory tests, eye exams, office visits and foot exams. We also investigate the relationship between patient out of pocket cost-sharing and adherence to the recommended diabetes management regimen. Finally, we investigate the cost implications of adherence to a recommended regimen of care.
Population Studied: Patients with type 2 diabetes age 18 to 64 years who filled at least one prescription for an oral antidiabetic medication and visited a physician at least one time were found in the MarketScan Research Database (n=91,192). These individuals received insurance coverage through large and medium sized employers and were continuously enrolled from January 2003 through June 2006.
Methods: We constructed several measures of chronic maintenance adherence including a dichotomous measure of adherence to guidelines within an eighteen month time frame. We also constructed a weighted composite adherence scores with weights developed using factor analysis and regression and separately for medical services and medical plus prescription drug services. We investigated the relationship between patient cost-sharing and adherence via multivariate generalized linear models (GLM). We also investigated the relationship between adherence and subsequent spending in the next two years via GLM, and examine whether the effects of adherence are due to the endogeneity of patients selecting into adherent behavior.
Results: All individual measures of adherence were positively correlated with the highest correlation between all types of laboratory tests and the lowest correlation between foot exams and other medical tests (all p<0.01). As the out-of-pocket price of adherence to the regimen of diabetes care rose (cost-sharing amount), adherence to the regimen of care declined. If the amount of patient cost-sharing to the regimen was doubled, adherence declined 8% (p<0.01). We found little evidence of selection affects into prescription adherence behavior, and determined that patients adherent to prescription drugs had medical costs in that were 11.9% (p<0.01) below nonadherent patients. However, patients that were adherent to a composite of medical care services had higher levels of spending. We analyze and investigate methods to control for selection into adherence for medical care services.
Conclusions: Patients who are adherent to one component of a regimen of chronic care management are likely to be adherent to other components of care. Cost-sharing for prescription drug and medical care services can be a financial barrier to adherence to recommended care.
Implications: Reducing barriers to chronic care management for both medical and prescription drug services are likely to improve adherence to recommended guidelines and may have a significant effect on costs.
The 3rd Biennial Conference of the American Society of Health Economists took place at Cornell University.
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